A mathematics model of double-action variable displacement plunger pump was built for sugarcane harvester based on power bond graph. Some nonlinear influence factors were linearized or neglected for the model. The response characteristic of flow, pressure and reversing were analyzed in Matlab/Simulink by changing swash plate angle of Eaton series 1 model No.64 displacement plunger pump. The results showed that the proposed double-action variable displacement plunger pump had good dynamic response characteristics. It could meet the requirements of the hydraulic drive system on sugarcane harvester.